From: "Kirill A. Shutemov" Subject: [PATCHv1, RFC 05/33] radix-tree: Add radix_tree_split_preload() Date: Tue, 26 Jul 2016 03:35:07 +0300 Message-ID: <1469493335-3622-6-git-send-email-kirill.shutemov@linux.intel.com> References: <1469493335-3622-1-git-send-email-kirill.shutemov@linux.intel.com> Cc: Alexander Viro , Hugh Dickins , Andrea Arcangeli , Andrew Morton , Dave Hansen , Vlastimil Babka , Matthew Wilcox , Ross Zwisler , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, Matthew Wilcox , "Kirill A . Shutemov" To: "Theodore Ts'o" , Andreas Dilger , Jan Kara Return-path: In-Reply-To: <1469493335-3622-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org From: Matthew Wilcox Calculate how many nodes we need to allocate to split an old_order entry into multiple entries, each of size new_order. The test suite checks that we allocated exactly the right number of nodes; neither too many (checked by rtp->nr == 0), nor too few (checked by comparing nr_allocated before and after the call to radix_tree_split()). Signed-off-by: Matthew Wilcox Signed-off-by: Kirill A. Shutemov --- include/linux/radix-tree.h | 1 + lib/radix-tree.c | 22 ++++++++++++++++++++++ tools/testing/radix-tree/multiorder.c | 28 ++++++++++++++++++++++++++-- tools/testing/radix-tree/test.h | 9 +++++++++ 4 files changed, 58 insertions(+), 2 deletions(-) diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 7e906a270664..2f1404303bcc 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -318,6 +318,7 @@ static inline void radix_tree_preload_end(void) preempt_enable(); } +int radix_tree_split_preload(unsigned old_order, unsigned new_order, gfp_t); int radix_tree_split(struct radix_tree_root *, unsigned long index, unsigned new_order); int radix_tree_join(struct radix_tree_root *, unsigned long index, diff --git a/lib/radix-tree.c b/lib/radix-tree.c index e69f1053cd78..e49f32f7c537 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -404,6 +404,28 @@ int radix_tree_maybe_preload(gfp_t gfp_mask) } EXPORT_SYMBOL(radix_tree_maybe_preload); +#ifdef CONFIG_RADIX_TREE_MULTIORDER +/* + * Preload with enough objects to ensure that we can split a single entry + * of order @old_order into many entries of size @new_order + */ +int radix_tree_split_preload(unsigned int old_order, unsigned int new_order, + gfp_t gfp_mask) +{ + unsigned top = 1 << (old_order % RADIX_TREE_MAP_SHIFT); + unsigned layers = (old_order / RADIX_TREE_MAP_SHIFT) - + (new_order / RADIX_TREE_MAP_SHIFT); + unsigned nr = 0; + + WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); + BUG_ON(new_order >= old_order); + + while (layers--) + nr = nr * RADIX_TREE_MAP_SIZE + 1; + return __radix_tree_preload(gfp_mask, top * nr); +} +#endif + /* * The same as function above, but preload number of nodes required to insert * (1 << order) continuous naturally-aligned elements. diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c index 9d27a4dd7b2a..5eda47dfe818 100644 --- a/tools/testing/radix-tree/multiorder.c +++ b/tools/testing/radix-tree/multiorder.c @@ -348,18 +348,42 @@ static void multiorder_join(void) } } +static void check_mem(unsigned old_order, unsigned new_order, unsigned alloc) +{ + struct radix_tree_preload *rtp = &radix_tree_preloads; + if (rtp->nr != 0) + printf("split(%u %u) remaining %u\n", old_order, new_order, + rtp->nr); + /* + * Can't check for equality here as some nodes may have been + * RCU-freed while we ran. But we should never finish with more + * nodes allocated since they should have all been preloaded. + */ + if (nr_allocated > alloc) + printf("split(%u %u) allocated %u %u\n", old_order, new_order, + alloc, nr_allocated); +} + static void __multiorder_split(int old_order, int new_order) { - RADIX_TREE(tree, GFP_KERNEL); + RADIX_TREE(tree, GFP_ATOMIC); void **slot; struct radix_tree_iter iter; + unsigned alloc; - item_insert_order(&tree, 0, old_order); + radix_tree_preload(GFP_KERNEL); + assert(item_insert_order(&tree, 0, old_order) == 0); + radix_tree_callback(NULL, CPU_DEAD, NULL); radix_tree_tag_set(&tree, 0, 2); + + radix_tree_split_preload(old_order, new_order, GFP_KERNEL); + alloc = nr_allocated; radix_tree_split(&tree, 0, new_order); + check_mem(old_order, new_order, alloc); radix_tree_for_each_slot(slot, &tree, &iter, 0) { radix_tree_replace_slot(slot, item_create(iter.index)); } + radix_tree_preload_end(); item_kill_tree(&tree); } diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h index e85131369723..55e6d095047b 100644 --- a/tools/testing/radix-tree/test.h +++ b/tools/testing/radix-tree/test.h @@ -2,6 +2,8 @@ #include #include #include +#include +#include struct item { unsigned long index; @@ -43,3 +45,10 @@ void radix_tree_dump(struct radix_tree_root *root); int root_tag_get(struct radix_tree_root *root, unsigned int tag); unsigned long node_maxindex(struct radix_tree_node *); unsigned long shift_maxindex(unsigned int shift); +int radix_tree_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu); +struct radix_tree_preload { + unsigned nr; + struct radix_tree_node *nodes; +}; +extern struct radix_tree_preload radix_tree_preloads; -- 2.8.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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